The Largest Russian Manufacturer of Rock Bits
Geological Formation Definition

Non-abrasive soft Soft shales, clays, soft sandstone, gypsum, loose gravels, and silts
medium Medium to hard shales, hard sandstones, and medium limestones
hard Hard limestones, dolomite, hard highly cemented sandstones, and granite
special Very hard limestones, dolomites, and granites, quartz, andecite and andecite-basalts
Abrasive soft Soft semi abrasive sandstones, soft semi abrasive shales, unconsolidated overburdens, and silicifed siltstones 
medium Semi abrasive medium hard sandstones, limestones, unconsolidated medium hard coal overburden, medium porphry copper, basalt, chert, and other formations with silicious properties
hard Hard unconsolidated gold formations, hard silicious limestones, quartz, taconite, granite, dolomite, chert, porphry copper, and other formations that have high silica and quartz content
special Very hard cemented iron formations, hematite, specular hematite, magnitite, gold formations, abrasive iron ore, marblized limestone, and flint

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